JPS6217073B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of enlarging and excavating the outer circumference of an already excavated normal-diameter tunnel, and particularly to a method for enlarging and excavating a tunnel by varying the diameter of the enlarged excavation or making it eccentric. It is related to construction methods.

The shield method is often used as an excellent construction method for tunnel excavation for subway construction and underground cable burying work, but when building subway stations or connecting underground cables, it is often necessary to use the shield method. It becomes necessary to enlarge the section. The conventional method for carrying out the above expansion work is to dig a shaft from the ground in the area where the tunnel is planned to be expanded, which was constructed using the shield method, and then use this shaft to construct the expanded tunnel. Ta.

However, the above construction method has become increasingly difficult to implement in recent years, especially in urban areas due to restrictions on the construction of various above-ground and underground structures, and the shafts that have been excavated have to be backfilled, except for a portion, after the expansion work. There was also a problem in terms of cost, as it did not work.

Therefore, the applicant of the present application previously proposed in Japanese Patent Application No. 56-153966 (Japanese Unexamined Patent Publication No. 58-98593) a tunnel enlargement excavation method that improves the above-mentioned conventional method. This new construction method involves excavating a normal-diameter tunnel using a primary shield machine, then removing the primary segment at one end of the area scheduled for expansion and performing enlarged excavation to construct a starting base, and then assembling and installing the expanded This is a construction method in which a shield machine is propelled in the axial direction along the outer circumference of a normal diameter tunnel, and the enlarged section is constructed by performing widening work while removing the primary segment and attaching the secondary segment to the enlarged excavated section.

Therefore, the present application proposes an enlarged tunnel excavation method suitable for carrying out enlarged excavation within a relatively short range in the axial direction, such as the above-mentioned starting base, and the gist of the present application is as follows.

This is a construction method in which the primary segments of the area to be expanded, which are usually installed in a tunnel, are sequentially removed and the outer circumference is enlarged and excavated, and a built-in propulsion jack with a cutting edge formed on the propulsion tip side is used to excavate the outer circumference of the normal diameter tunnel. The proximal end side of a circumferential shield machine that excavates along the tunnel is rotatably supported by a guide ring, and this guide ring is formed to have a smaller diameter than the primary segment and is installed in the normal diameter tunnel, and is connected to the normal diameter tunnel. When enlarging excavation in a concentric manner, the center of the guide ring is aligned with the center of the normal diameter tunnel, and when enlarging excavation in an eccentric manner, the center of the guide ring is eccentrically positioned at both ends of the area to be expanded. A tunnel expansion excavation method characterized in that the guide ring is attached to the primary segment, and enlarged excavation can be performed in an appropriate concentric or eccentric manner by changing the attachment position of the guide ring.

As a result, there is no need to provide a vertical shaft when carrying out enlarged excavation, and enlarged excavation can be carried out efficiently in the area to be enlarged by parallel work with normal diameter tunnel excavation. In particular, by changing the mounting position of the guide ring that guides the proximal end of the circumferential shield machine, it is possible to carry out any enlarged excavation concentrically or eccentrically with respect to the normal diameter tunnel. This is a tunnel expansion excavation method.

Examples of the construction method of the present invention will be described below with reference to the drawings.

First, as shown in FIGS. 1 and 2, among the primary segments 3 on the outer periphery of the normal diameter tunnel 1 in the area to be expanded 2, the lower primary segment 3a is removed, and the primary segment in the area to be expanded is removed. Guide rings 5 and 6 are mounted on the inner surface of the primary segment 4 adjacent to the segment 3, respectively.

The guide rings 5 and 6 are formed by joining together arc-shaped guide ring pieces each having a U-shaped cross section, and have a diameter smaller than the inner diameter of the tunnel 1 having a normal diameter at least. The center O ₂ of the tunnel 6 is located eccentrically from the center O ₁ of the tunnel 1 of normal diameter. The proximal end side of the circumferential shield machine 7 is rotatably mounted on each of the guide rings 5 and 6, respectively.

Although detailed illustration of the circumferential shield machine 7 is omitted,
Like a general shield machine, a cutting edge is formed at the tip of the propulsion side, and a propulsion jack is built in, and the cross section is approximately U-shaped with an arcuate outer circumferential side. The circumferential shield machine 7, whose proximal end is rotatably supported by these guide rings 6 and 7, is installed by locally excavating the ground below the removed primary segment 3a. , a reaction force receiving plate 8 is installed on the ground surface on the opposite side of the direction in which the circumferential shield machine 7 is propelled.
is installed.

Next, when enlarging excavation by propelling the circumferential shield machine 7 in the direction of the arrow, first remove the primary segment 3b in front and attach the propulsion jack built in the circumferential shield machine (not shown) to the reaction force receiving plate. 8 as a reaction force receiver, the machine moves forward while digging the cutting edge into the ground in front of it, and excavates the earth and sand inside the circumferential shield machine.

A circumferential segment 9 having an arcuate outer circumferential side and a U-shaped cross section is installed in the rear enlarged portion caused by the excavation of the circumferential shielding machine 7, and the circumferential segment 9 is After inserting piece materials 10, 10 between the primary segment 4 adjacent to the planned expansion area 2 as shown in FIG. 3, the primary segment 4, the piece material 10, and the circumferential segment 9 are bolted do.

In the subsequent enlarged excavation, the reaction force is sequentially received by the newly installed circumferential segment 9 instead of the reaction force receiving plate 8, and the primary segment 3 on the propulsion side is
The circumferential shielding machine 7 guided by the guide rings 5 and 6 is propelled along the outer periphery of the normal diameter tunnel 1 while sequentially removing the tunnels 1 and 2, and the desired enlarged excavation is performed over the entire circumference.

Through this enlarged excavation, the periphery is earth-retained with circumferential segments 9 as shown in FIGS. 4 and 5, and an enlarged tunnel 11 eccentric to the normal diameter tunnel 1 is constructed.

In other words, by mounting the guide rings 5 and 6 with their centers _O2 shifted upwards from the center _O1 of the normal diameter tunnel 1, the upper enlarged excavation part is larger and the lower enlarged excavation part is smaller due to the eccentric circle. This means that expanded excavation has been carried out.

Therefore, by appropriately changing the center of the guide ring with respect to the center of the normal diameter tunnel, it is possible to perform enlarged excavation with any eccentric circle.

Next, FIG. 6 shows another embodiment of the present application, and for ease of understanding, the same members as in the previous embodiment are indicated by the same reference numerals. In this embodiment, a plurality of cylinders 12, 1 are provided on the outer periphery of each guide ring 5, 6.
3, and each guide ring is fixed to the primary segment 4 via the cylinders 12 and 13.

That is, by expanding and contracting each of the cylinders 12 and 13 to an arbitrary length, it becomes possible to appropriately change the center of the guide rings 5 and 6 with respect to the center of the normal diameter tunnel 1, and it is possible to easily enlarge and excavate eccentric circles and concentric circles. I can do it.

As mentioned above, the tunnel expansion excavation method of the present application is
A guide ring that guides the circumferential shield machine that is propelled along the circumference is formed smaller than the inner diameter of the normal diameter tunnel and installed inside the normal diameter tunnel, thereby allowing arbitrary enlarged excavation. It is.

In the above embodiment, concentric circles and eccentric circles are illustrated, but by changing the shape of the guide ring, it is possible to perform concentric or eccentric elliptical enlarged excavation,
It is also possible to perform enlarged rectangular excavation with gentle arcs at the four corners.

[Brief explanation of the drawing]

Figure 1 and Figure 3 are process explanatory drawings showing the excavation method of the present application, Figure 2 is a sectional view taken along the line - - in Figure 1, Figure 4 is an end view of the enlarged tunnel in the completed state, and Figure 5 is the same as in Figure 4. - line sectional view, FIG. 6 is a sectional view similar to FIG. 2 according to another embodiment. Explanation of symbols, 1...Normal diameter tunnel, 2...Expansion planned area, 3, 4...Primary segment, 5, 6
...Guide ring, 7...Circumferential shield machine, 8...
... Reaction force receiving plate, 9 ... Circumferential segment, 10 ... Piece material, 11 ... Expansion tunnel, 12, 13 ...
Cylinder, O ₁ ... Center of normal diameter tunnel, O ₂ ...
...The center of the guide ring.

Claims (1)

[Claims] 1. This is a construction method in which the primary segments of the area to be expanded that are installed in a normal tunnel are sequentially removed and the outer circumference is enlarged and excavated. The proximal end side of a circumferential shield machine that excavates along the outer periphery is rotatably supported by a guide ring, and this guide ring is formed to have a smaller diameter than the primary segment and is provided in the normal diameter tunnel, and the guide ring is provided in the normal diameter tunnel. When enlarging excavation in a concentric manner, align the center of the guide ring with the center of the normal diameter tunnel,
In addition, when expanding excavation in an eccentric manner, the center of the guide ring is eccentrically attached to the primary segment at both ends of the area to be expanded, and by changing the attachment position of the guide ring, it is possible to perform concentric or eccentric excavation as appropriate. A tunnel expansion excavation method characterized by enabling expanded excavation.